Additive amortisseur circuit

ABSTRACT

A method of manufacturing a rotor of an electric motor or an electric generator includes positioning a plurality of amortisseur bars and using additive manufacturing to place electrically conductive material. More specifically, positioning the amortisseur bars may include circumferentially positioning the bars around a rotor stack and using additive manufacturing to place electrically conductive material may include forming a non-solid pattern of electrically conductive material, such as a pattern of electrically conductive traces, across opposite axial ends of the rotor stack to electrically interconnect an amortisseur circuit.

FIELD

The present disclosure relates to electric motors or electricgenerators, and more specifically, to amortisseur circuits of rotors.

BACKGROUND

Most conventional electric motors and/or electric generators have arotor made of separate planar members of ferromagnetic material that areheld together by a binder, such as an epoxy. Rotors also generallyinclude a plurality of amortisseur bars that extend along the rotorstack between opposite axial ends of the rotor stack. Conventionalrotors further include end laminations that help to hold the rotor stacktogether and that, together with the amortisseur bars, form anamortisseur circuit. Conventional end laminations are often brazed tothe opposite ends of the rotor stack. Brazing generally involvesintroducing heat to the rotor stack assembly, and this heat may lead tolocalized hotspots that may degrade the mechanical properties of therotor stack. Additionally braze filler material may flow into undesiredareas of the rotor stack, or binders/adhesives of the rotor stack mayvolatize, further degrading the structural integrity of the rotor stack.Still further, end laminations are often heavy and may add excessiveweight to the electric motor.

SUMMARY

In various embodiments, the present disclosure provides a method ofmanufacturing a rotor for an electric motor or an electric generator.The method may include positioning a plurality of amortisseur barscircumferentially around a rotor stack, wherein the plurality ofamortisseur bars extend between a first axial end of the rotor stack anda second axial end of the rotor stack opposite the first axial end. Themethod may also include additively manufacturing electrically conductivematerial on the first axial end and the second axial end of the rotorstack and electrically interconnecting the plurality of amortisseur barstogether via the electrically conductive material to form an amortisseurcircuit.

In various embodiments, the step of positioning the plurality ofamortisseur bars is performed before additively manufacturing theelectrically conductive material. In various embodiments, positioningthe plurality of amortisseur bars is performed after additivelymanufacturing the electrically conductive material. In variousembodiments, positioning the plurality of amortisseur bars includesadditively manufacturing the amortisseur bars.

In various embodiments, additively manufacturing the electricallyconductive material includes forming a pattern of electricallyconductive traces. In various embodiments, the pattern includes aplurality of radially extending traces. In various embodiments, thepattern includes a mesh-like formation of electrically conductivetraces.

Also disclosed herein, according to various embodiments, is a rotor ofan electric motor or an electric generator. The rotor may include arotor stack having a central longitudinal axis, a first axial end, and asecond axial end opposite the first axial end. The rotor may include aplurality of amortisseur bars circumferentially distributed around andradially outward of the central longitudinal axis of the rotor stack.The plurality of amortisseur bars may extend substantially parallel tothe central longitudinal axis between the first axial end and the secondaxial end. The rotor may further include a first layer of electricallyconductive material on the first axial end of the rotor stack and asecond layer of electrically conductive material on the second axial endof the rotor stack. In various embodiments, the first layer and thesecond layer each includes a non-solid pattern of electricallyconductive traces.

In various embodiments, any cross-section, perpendicular to the centrallongitudinal axis, of the first layer and the second layer defines atleast one gap. The at least one gap may be radially positioned betweenadjacent amortisseur bars of the plurality of amortisseur bars. Invarious embodiments, the non-solid pattern of electrically conductivetraces comprises a plurality of radially extending traces. In variousembodiments, the non-solid pattern of electrically conductive tracescomprises a mesh-like formation of electrically conductive traces. Invarious embodiments, the first axial end and the second axial end arefree of electrically conductive lamination layers. Also disclosedherein, according to various embodiments, is an electric motor thatincludes a stator and the rotor as described above.

The foregoing features and elements may be combined in variouscombinations without exclusivity, unless expressly indicated hereinotherwise. These features and elements as well as the operation of thedisclosed embodiments will become more apparent in light of thefollowing description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an electric machine, such as an electricmotor or an electric generator, in accordance with various embodiments;

FIG. 2A is a perspective view of a channel defined in a rotor stack foran amortisseur bar, in accordance with various embodiments;

FIG. 2B is an end view of a rotor stack before amortisseur bars areprovided, in accordance with various embodiments;

FIG. 3A is a perspective view of an amortisseur bar of a rotor stack andan additively manufactured conductive material disposed on an end of therotor stack, in accordance with various embodiments;

FIG. 3B is an end view of a rotor stack showing a pattern of additivelymanufactured conductive material, in accordance with variousembodiments;

FIG. 4A is a perspective view of an amortisseur bar of a rotor stack andan additively manufactured conductive material disposed on an end of therotor stack, in accordance with various embodiments;

FIG. 4B is an end view of a rotor stack showing a pattern of additivelymanufactured conductive material, in accordance with variousembodiments;

FIG. 5A is a perspective view of an amortisseur bar of a rotor stack andan additively manufactured conductive material disposed on an end of therotor stack, in accordance with various embodiments;

FIG. 5B is an end view of a rotor stack showing a pattern of additivelymanufactured conductive material, in accordance with variousembodiments; and

FIG. 6 is a schematic flow chart diagram of a method of manufacturing arotor stack, in accordance with various embodiments.

The subject matter of the present disclosure is particularly pointed outand distinctly claimed in the concluding portion of the specification. Amore complete understanding of the present disclosure, however, may bestbe obtained by referring to the detailed description and claims whenconsidered in connection with the drawing figures, wherein like numeralsdenote like elements.

DETAILED DESCRIPTION

The detailed description of exemplary embodiments herein makes referenceto the accompanying drawings, which show exemplary embodiments by way ofillustration. While these exemplary embodiments are described insufficient detail to enable those skilled in the art to practice thedisclosure, it should be understood that other embodiments may berealized and that logical changes and adaptations in design andconstruction may be made in accordance with this disclosure and theteachings herein without departing from the spirit and scope of thedisclosure. Thus, the detailed description herein is presented forpurposes of illustration only and not of limitation.

In various embodiments, and with reference to FIG. 1, an electricmachine 100, such as an electric motor or an electric generator, havingan additively manufactured amortisseur circuit is disclosed herein. Theelectric machine 100 generally includes a stator 105 and a rotor 110.The amortisseur circuit includes a plurality of amortisseur bars 120extending along a rotor 110 and an electrically conductive material 130formed, via additive manufacturing techniques, on opposite ends of therotor stack. Although the electrically conductive material 130 isrepresented as parallel hatching in FIG. 1, the electrically conductivematerial 130, as described in greater detail below, generally refers toa non-solid pattern of material (e.g., not a lamination layer).Accordingly, the pattern of the electrically conductive material 130formed on opposite ends of the rotor 110 is not limited to the hatchingpattern shown in FIG. 1. Thus, the hatching pattern of FIG. 1schematically represents the traces of electrically conductive material130. In various embodiments, the electric machine 100 is an electricmotor or an electric generator of an aircraft.

As used herein, and with continued reference to FIG. 1, the terms axial,radial, and circumferential are relative to the central longitudinalaxis 115 of the rotor 110. That is, a first component that is “radiallyoutward” of a second component means that the first component ispositioned at a greater distance away from the central longitudinal axis115 of the rotor 110 than the second component. Correspondingly, a firstcomponent that is “radially inward” of a second component means that thefirst component is positioned closer to axis 115 than the secondcomponent. Accordingly, in the case of the rotor 110, components thatare radially inward of other components and that rotatecircumferentially about the central longitudinal axis 115 rotatesthrough a circumferentially shorter path than the other components.Similarly, the term “axial” generally refers to a position along thecentral longitudinal axis 115.

In various embodiments, and with reference to FIGS. 1, 2A, and 2B, therotor 110, also referred to herein as “rotor stack” 110, includes aplurality of separate planar members of ferromagnetic material 116 thatare held together by a binder or an adhesive. The rotor stack 110 may bemade from iron or iron alloys, such as ferrosilicon, among otherferromagnetic materials. In various embodiments, and with reference toFIGS. 1, 3A, and 3B, rotor stack 110 also includes a plurality ofamortisseur bars 120 that extend along the rotor stack 110 betweenopposite axial ends 111, 112 of the rotor stack. That is the rotor stack110 may have a first axial end 111 and a second axial end 112 oppositethe first axial end 111, and the amortisseur bars 120 may be configuredto have opposite ends that are flush or substantially planar with theaxial ends 111, 112 of the rotor stack 110.

In various embodiments, the amortisseur bars 120 are circumferentiallydistributed around central longitudinal axis 115 of the rotor 110. Invarious embodiments, the amortisseur bars 120 are radially outward ofthe central longitudinal axis 115 of the rotor 110 and may extendsubstantially parallel to the central longitudinal axis 115 (e.g., theamortisseur bars 120 may be skewed relative to the central longitudinalaxis 115, but generally extend longitudinally between opposing ends ofthe rotor 110). The amortisseur bars 120 may be disposed withinpreformed channels 114 (with momentary reference to FIGS. 2A and 2B) ofthe rotor stack. The channels 114 may facilitate retention of theamortisseur bars 120 and may contributed to the mechanical strength ofthe electric machine 100. In various embodiments, the amortisseur barsmay be only partially retained in channels, or the amortisseur bars maybe entirely external to the rotor stack 110.

In various embodiments, and with reference to FIG. 1, the rotor 110 alsoincludes an electrically conductive material 130 placed on the axialends 111, 112 of the rotor stack 110 via additive manufacturing.Additional details pertaining to the method of forming the electricallyconductive material 130 on the axial ends 111, 112 of the rotor stack110 are included below with reference to FIG. 6. In various embodiments,electrically conductive material is deposited via additive manufacturingon both axial ends 111, 112 of the rotor stack. For example, a firstlayer of electrically conductive material may be disposed/placed/formedon the first axial end 111 of the rotor stack 110 and a second layer ofelectrically conductive material may be disposed/placed/formed on thesecond axial end 112 of the rotor stack. In various embodiments, theelectrically conductive material (e.g., the first and second layers ofelectrically conductive material) forms a non-solid pattern ofelectrically conductive traces. Said differently, any cross-section,perpendicular to the central longitudinal axis 115 of the rotor stack110, of the electrically conductive material (e.g., the first and secondlayers of electrically conductive material) defines at least one gap.That is, the electrically conductive material 130 is not a solid plateof material and is not a lamination layer at opposite axial ends of therotor stack 110. Thus, the axial ends 111, 112 of the rotor 110 may befree of electrically conductive lamination layers. Utilizing additivemanufacturing to apply a plurality of electrically conductive tracesacross the axial ends 111, 112 of the rotor 110 decreases manufacturingcosts, compared with using conventional end lamination plates.

In various embodiments, and with reference to FIGS. 3A and 3B, thenon-solid pattern of the electrically conductive material disposed onthe axial ends 111, 112 of the rotor stack 110 is a plurality ofradially extending, electrically conductive traces 330. In variousembodiments, gaps 332 may be formed between adjacent electricallyconductive traces 330. The gaps 332 defined in the electricallyconductive layer by the electrically conductive traces 330 may at leastbe radially positioned between adjacent amortisseur bars 120. In variousembodiments, the non-solid pattern of electrically conductive materialincludes a ring 331 disposed radially inward of the amortisseur bars120, and the radially extending, electrically conductive traces 330extend between the amortisseur bars 120 and the ring 331.

In various embodiments, and with reference to FIGS. 4A and 4B, thenon-solid pattern of the electrically conductive material disposed onthe axial ends 111, 112 of the rotor stack 110 is a plurality ofradially extending traces 430. In various embodiments, gaps 432 may beformed between circumferentially adjacent traces 430. In variousembodiments, a plurality of radially extending traces 430 may extend toeach amortisseur bar 120 such that one or more gaps 432 are definedbetween circumferentially adjacent, radially extending traces 430 thatextend to each amortisseur bar 120.

In various embodiments, and with reference to FIGS. 5A and 5B, thenon-solid pattern of the electrically conductive material disposed onthe axial ends 111, 112 of the rotor stack 110 is a mesh-like formationof electrically conductive traces 530. In various embodiments, gaps 532may be formed between the traces 530. As mentioned above, the gaps 532defined in the electrically conductive layer by the electricallyconductive traces 530 may at least be radially positioned betweenadjacent amortisseur bars 120. In various embodiments, the electricallyconductive material may include other patterns of traces, such asstar-shaped or otherwise.

In various embodiments, the traces 430, 530 of electrically conductivematerial may not completely cover the axial ends of the amortisseur bars120, but instead may terminate in electrical connection with theamortisseur bars 120, as shown in FIGS. 4A, 4B, 5A, and 5B. In variousembodiments, the non-solid pattern of electrically conductive materialextends over the axial ends of the amortisseur bars 120. In variousembodiments, the electrically conductive material includes copper,copper alloy, aluminum, aluminum alloys, nickel, nickel based alloys,titanium-based materials, or electrically conductive carbon materials,among others.

In various embodiments, forming a non-solid pattern of electricallyconductive material 130 on opposite axial ends 111, 112 of the rotorstack 110 via additive manufacturing provides various benefits oversolid end-plate brazing techniques. The non-solid pattern ofelectrically conductive material 130, such as the pattern formed bytraces 430 and traces 530, enables the amortisseur circuit to becompleted while reducing the amount and weight of material used,according to various embodiments. Further, the rotation dynamics of therotor 110 may be tuned, at least to a degree, using different patternsof traces, according to various embodiments. Still further, forming thenon-solid pattern of electrically conductive material via additivemanufacturing does not expose the rotor stack 110 to excessivetemperatures and thus the rotor stack 110 does not experience localizedhot spots, as would otherwise occur if conventional sold end-platebrazing techniques were employed, according to various embodiments.

In various embodiments, and with reference to FIG. 6, a method 690 ofmanufacturing a rotor 110 for an electric machine 100, such as anelectric motor or an electric generator, is provided. The method 690 mayinclude positioning a plurality of amortisseur bars 120circumferentially around a rotor stack 110 at step 692 and usingadditive manufacturing to place electrically conductive material 130 onaxial ends 111, 112 of the rotor stack 110 at step 694. In variousembodiments, the steps 692, 694 of the method 690 electricallyinterconnect an amortisseur circuit that includes the plurality ofamortisseur bars 120 and the electrically conductive material 130. Invarious embodiments, the phrase “using additive manufacturing” refers toincremental material deposition. In various embodiments, step 694includes a high velocity oxy fuel (“HVOF”) procedure, a micro-HVOFprocedure, plasma arc deposition, or directed energy deposition additivemanufacturing, among other technologies.

In various embodiments, step 692 is performed before step 694. That is,the amortisseur bars 120 may be in place within channels 114 of a rotorstack 110 or disposed external to the rotor stack 110 before usingadditive manufacturing to form the non-solid pattern of electricallyconductive material. In various embodiments, step 692 is performed afterstep 694. That is, the electrically conductive material may be firstformed on opposite axial ends 111, 112 of the rotor stack 110 beforepositioning the amortisseur bars 120 within channels 114 or otherwiseplacing the amortisseur bars 120. In various embodiments, step 692 isperformed using additive manufacturing. That is, the amortisseur bars120 themselves may be formed via additive manufacturing.

Benefits, other advantages, and solutions to problems have beendescribed herein with regard to specific embodiments. Furthermore, theconnecting lines shown in the various figures contained herein areintended to represent exemplary functional relationships and/or physicalcouplings between the various elements. It should be noted that manyalternative or additional functional relationships or physicalconnections may be present in a practical system. However, the benefits,advantages, solutions to problems, and any elements that may cause anybenefit, advantage, or solution to occur or become more pronounced arenot to be construed as critical, required, or essential features orelements of the disclosure.

The scope of the disclosure is accordingly to be limited by nothingother than the appended claims, in which reference to an element in thesingular is not intended to mean “one and only one” unless explicitly sostated, but rather “one or more.” It is to be understood that unlessspecifically stated otherwise, references to “a,” “an,” and/or “the” mayinclude one or more than one and that reference to an item in thesingular may also include the item in the plural. All ranges and ratiolimits disclosed herein may be combined.

Moreover, where a phrase similar to “at least one of A, B, and C” isused in the claims, it is intended that the phrase be interpreted tomean that A alone may be present in an embodiment, B alone may bepresent in an embodiment, C alone may be present in an embodiment, orthat any combination of the elements A, B and C may be present in asingle embodiment; for example, A and B, A and C, B and C, or A and Band C. Different cross-hatching is used throughout the figures to denotedifferent parts but not necessarily to denote the same or differentmaterials.

The steps recited in any of the method or process descriptions may beexecuted in any order and are not necessarily limited to the orderpresented. Furthermore, any reference to singular includes pluralembodiments, and any reference to more than one component or step mayinclude a singular embodiment or step. Elements and steps in the figuresare illustrated for simplicity and clarity and have not necessarily beenrendered according to any particular sequence. For example, steps thatmay be performed concurrently or in different order are illustrated inthe figures to help to improve understanding of embodiments of thepresent disclosure.

Any reference to attached, fixed, connected or the like may includepermanent, removable, temporary, partial, full and/or any other possibleattachment option. Additionally, any reference to without contact (orsimilar phrases) may also include reduced contact or minimal contact.Surface shading lines may be used throughout the figures to denotedifferent parts or areas but not necessarily to denote the same ordifferent materials. In some cases, reference coordinates may bespecific to each figure.

Systems, methods and apparatus are provided herein. In the detaileddescription herein, references to “one embodiment,” “an embodiment,”“various embodiments,” etc., indicate that the embodiment described mayinclude a particular feature, structure, or characteristic, but everyembodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it may be within the knowledge of oneskilled in the art to affect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed. After reading the description, it will be apparent to oneskilled in the relevant art(s) how to implement the disclosure inalternative embodiments.

Furthermore, no element, component, or method step in the presentdisclosure is intended to be dedicated to the public regardless ofwhether the element, component, or method step is explicitly recited inthe claims. No claim element is intended to invoke 35 U.S.C. 112(f)unless the element is expressly recited using the phrase “means for.” Asused herein, the terms “comprises,” “comprising,” or any other variationthereof, are intended to cover a non-exclusive inclusion, such that aprocess, method, article, or apparatus that comprises a list of elementsdoes not include only those elements but may include other elements notexpressly listed or inherent to such process, method, article, orapparatus.

What is claimed is:
 1. A method of manufacturing a rotor for an electricmotor or an electric generator, the method comprising: positioning aplurality of amortisseur bars circumferentially around a rotor stack,wherein the plurality of amortisseur bars extend between a first axialend of the rotor stack and a second axial end of the rotor stackopposite the first axial end; and additively manufacturing electricallyconductive material on the first axial end and the second axial end ofthe rotor stack; and electrically interconnecting the plurality ofamortisseur bars together via the electrically conductive material toform an amortisseur circuit.
 2. The method of claim 1, whereinadditively manufacturing the electrically conductive material isperformed after positioning the plurality of amortisseur bars.
 3. Themethod of claim 1, wherein positioning the plurality of amortisseur barsis performed after additively manufacturing the electrically conductivematerial.
 4. The method of claim 1, wherein positioning the plurality ofamortisseur bars comprises additively manufacturing the amortisseurbars.
 5. The method of claim 1, wherein additively manufacturing theelectrically conductive material comprises forming a pattern ofelectrically conductive traces.
 6. The method of claim 5, wherein thepattern comprises a plurality of radially extending traces.
 7. Themethod of claim 5, wherein the pattern comprises a mesh-like formationof electrically conductive traces.
 8. The method of claim 1, whereinadditively manufacturing the electrically conductive material comprisesplasma arc deposition.